The present invention relates to an articulated robot wrist, comprising:                a first support that is to be mounted on a robot component that is rotatable about a first axis;        a second support mounted on said first support in a rotatable way about a second axis inclined with respect to said first axis;        a first motor, carried by said first support, the shaft of which is connected in rotation to said second support via a first gear transmission;        a third support, mounted on said second support in a rotatable way about a third axis inclined with respect to said second axis; and        a second motor, the shaft of which is connected in rotation to said third support via a second gear transmission.        
A robot wrist of the type referred to above has formed the subject of the Italian patent application No. TO1996A000061.
The known solution referred to above presented all the characteristics defined previously. A particularly advantageous peculiarity of said solution was the possibility of having available, within the structure of the wrist, cables and/or ducts for supply of electrical energy and/or fluids to the equipment mounted on the wrist of the robot itself. In order to obtain this characteristic, the two motors were mounted in a retracted area of the first support, far from the end of the wrist carrying the equipment. The motions of rotation coming from the motors were transferred to the second support and the third support by means of a transmission system comprising hollow concentric transmission shafts that presented at their ends cylindrical and bevel gears, members for transmission of the motion, and rolling-bearing supporting elements.
The fabrication of a wrist according to the known solution thus implied the use of a large number of components, which rendered the transmission extremely costly and complicated. Furthermore, the precision of the movements suffered from the superposition of effects due to the possible play between the elements of the different transmissions.
In order to simplify the known solution described above, the subject of the present invention is an articulated robot wrist of the type referred to at the outset, characterized in that said second motor is carried by said second support.
Said particular arrangement, by producing an advance of the motors towards the respective controlled members, enables a drastic reduction in the number of the components of the transmission, albeit keeping free within the wrist the cavity pre-arranged for passage of the cables and/or supply ducts.
According to a particularly advantageous embodiment, each motor transmits the motion to the corresponding support by means of the use of a single gear pair.